Re: How to make a REALLY FAST db server? - Mailing list pgsql-general

I second the RAM point.  Not only is more better, you also need to configure
postgres to use it.  You will need to take the average size of your
backends, the number of concurrent connections you expect and the amount of
RAM you want postgres to leave for the OS and all the other processes.  This
will let you back into the proper buffer setting to best use the available
RAM without letting the postmaster go to swap space.  Buffers are not the
only variable for memory.  You need to allow space in ram for sort memory as
well.

As far as disks go.  You cannot have too many spindles.  But the number of
spindles you have available depends on which pieces of postgres get split
onto dedicated spindles.

A note on SMP.  Postgres is not a threaded application.  The best you can
hope for is that multiple connections get spread over multiple processors.
Each individual connection lives on a single CPU.

Tunning is somewhat of a black art to get the right balance.  If you have to
make a choice, buy fewer processors, faster disks, and as much RAM as the
board will handle.

--
Randy Hall - Red Hat Certified Engineer - Ex-Great Bridge PostgreSQL Expert
Resume: http://members.home.net/rthall3

----- Original Message -----
From: "Trond Eivind Glomsrød" <teg@redhat.com>
To: "bpalmer" <bpalmer@crimelabs.net>
Cc: <pgsql-general@postgresql.org>
Sent: Monday, September 10, 2001 4:54 PM
Subject: Re: [GENERAL] How to make a REALLY FAST db server?


> bpalmer <bpalmer@crimelabs.net> writes:
>
> > I'm looking to make a DB server for a project I'm working on (using
pgsql)
> > and am wondering if people have suggestions?
> >
> > Thoughts:
> >
> > - Hardware:  dual / quad Intel class
>
> Athlon gives more bang for the buck - the dual Athlons are _really_
> nice, and have proven stable as well.
>
> > - Disk:  SCSI Raid 1+0
>
> I'd probably go for a 3ware RAID instead... IDE disks are so much
> cheaper nowadays than SCSI, and the premium isn't really justifiable
> anymore.
>
> > - OS:  Prolly FreeBSD (FFS is your friend (what with syncs and all) and
it
> > can do multi proc support
>
> I'd recommend Linux, which has more mature MP support and scales
> better, but I'm obviously biased :). It's of course very important to
> keep what you are familiar with - a good sysadmin makes a world of
> difference no matter what you're using.
>
> > - Ram:  Not really sure here.  Is there math somewhere for ram needs for
> > pgsql? I imagine is has something to do with # connections,  db size,
> > etc.
>
> "More is better. RAM is cheap. Avoid RAMBUS".
>
> --
> Trond Eivind Glomsrød
> Red Hat, Inc.
>
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